The invention proceeds from an electrical machine having a control apparatus as described, for example, in EP 1 466 779 A2. The converter disclosed in said document is designed to reduce the electrical losses with semiconductor switching elements which, in generator mode, rectify the AC voltage which is delivered by the generator, and, in the motor mode, invert the voltage which is delivered by a DC voltage source. Semiconductor switching elements of this kind have a high degree of efficiency on account of low voltage drops during operation, but, on the other hand, there is an increased risk of damage to the switching elements under a high loading, in particular when used in a motor vehicle where severe fluctuations in temperature and loading often occur.